IRC Section 358: Basis Adjustments, Boot, and Holding Period

Under the basis rules of IRC Section 358, the stock or securities you receive in a tax-free corporate exchange take a basis equal to the adjusted basis of the property you gave up, decreased by any cash, other boot, and liabilities the other party assumed, and increased by any gain you recognized on the exchange. That single formula does most of the work. The rest is knowing which transactions it applies to, how to handle boot and multiple share classes, and where the traps sit.

When the Section 358 Formula Applies

Section 358 governs your basis whenever you exchange property for stock or securities in a transaction that qualifies for nonrecognition treatment under Sections 351, 354, 355, 356, or 361.¹ In practical terms, that covers:

Contributions of property to a controlled corporation under Section 351 (you and any co-transferors hold at least 80% of the voting power and shares right after the exchange).²
Stock-for-stock swaps in a corporate reorganization under Section 368 — mergers, acquisitive reorganizations, recapitalizations.³
Spin-offs, split-offs, and split-ups under Section 355, where a parent distributes subsidiary stock to its shareholders.⁴
Corporate-level exchanges under Section 361 where a corporation itself transfers assets in a reorganization plan.

A boundary worth stating up front: Section 358 tells the shareholder or transferor what basis to take in the stock received. The corporation’s basis in property it received from you runs on a separate track under Section 362.⁵ If your question is about the entity side, Section 358 is not your rule.

Start With the Basis of What You Gave Up

The starting number is the adjusted basis of the property surrendered. Hold Company A stock at a $100,000 basis, swap it for Company B stock in a tax-free reorganization, and Company B stock starts at $100,000. Because the transaction defers tax, your built-in gain or loss carries over into the new investment instead of being triggered now. This is called a substituted basis: the new property’s basis is determined by reference to the old property’s basis.¹

If you acquired the surrendered shares in multiple lots at different prices, you can’t just pool them. Treasury Regulation 1.358-2 requires you to trace each surrendered share to the specific new shares received for it, following the exchange terms if they specify the pairing. Where the terms are silent, a pro rata portion of each class received is treated as exchanged for each surrendered share. If you fail to designate at all, the IRS defaults to treating your earliest-purchased shares as exchanged first, which is often the worst outcome because those lots usually carry the lowest basis.⁶

The Adjustments That Change the Number

The starting basis is rarely the final basis. Section 358 layers in mandatory adjustments for everything else that moved in the exchange.¹

What Decreases Your Basis

Cash you received in the exchange, dollar for dollar.
The fair market value of any boot property received.
Any loss you recognized on the exchange.
Liabilities the other party assumed, treated as if you received cash.

What Increases Your Basis

Basis goes up by the total gain you recognized on the exchange. The statute splits this into gain treated as a dividend under Section 356 and gain not treated as a dividend, but the split only affects character on your return (ordinary dividend versus capital gain); the total increase equals the full recognized gain either way.⁷ The bump-up prevents double taxation: if you already paid tax on the boot-driven gain, that same gain shouldn’t hit you again when you eventually sell the stock.

Running the Numbers

A simple liability example. You contribute property with a $200,000 adjusted basis to a corporation under Section 351, and the corporation assumes your $50,000 mortgage. Stock basis: $200,000 start, minus $50,000 for the assumed debt, equals $150,000.

Now add boot. You surrender stock with a $100,000 basis in a reorganization and receive new stock plus $20,000 cash. Realized gain is $50,000, but Section 356 caps recognition at the $20,000 of boot received.⁷ Stock basis: $100,000 start, minus $20,000 for the cash, plus $20,000 for the recognized gain, equals $100,000. The recognized gain cancels the cash reduction, and the remaining $30,000 of deferred gain sits inside the new stock’s basis until you sell.

When Assumed Liabilities Exceed Your Basis

If the corporation assumes liabilities greater than the total adjusted basis of everything you transferred, Section 357(c) forces you to recognize the excess as gain. This applies to Section 351 transfers and certain divisive reorganizations.⁸

Say you transfer property with a $20,000 basis but a $30,000 mortgage. The $10,000 excess is recognized gain, characterized as capital or ordinary depending on the property. That recognized gain then increases your stock basis under Section 358, giving you a $10,000 basis rather than the negative figure the raw formula would produce.

One carve-out that catches people: certain deductible liabilities, like accounts payable whose future payment would generate a deduction, are excluded from the Section 357(c) calculation entirely.⁸ Sweep them in by mistake and you’ll recognize gain you don’t actually owe.

A separate anti-abuse rule, Section 358(h), addresses liability assumptions engineered to inflate basis. If, after all other adjustments, your stock basis exceeds the stock’s fair market value, Section 358(h) reduces your basis by the non-qualifying assumed liability amount, but not below fair market value. The rule doesn’t apply when the trade or business tied to the liability is also transferred in the exchange.¹

Basis of Boot Property

Boot property follows a different rule. Under Section 358(a)(2), non-cash boot takes a basis equal to its fair market value on the exchange date.¹ It does not inherit anything from the surrendered property; it starts fresh at FMV.

Watch for nonqualified preferred stock. Under Section 351(g), preferred shares with debt-like features (mandatory redemption at a fixed price, interest-rate-linked dividends, and similar terms) are treated as boot rather than qualifying stock.² Receiving it alongside regular stock in a Section 351 exchange reduces your regular stock basis and can trigger gain recognition, exactly the way cash boot does.

Splitting Basis Across Multiple Received Properties

Receive a single class of stock and the full basis attaches to it. Receive more than one class (common and preferred, stock in two different corporations, stock plus securities) and you allocate the total basis in proportion to the fair market values of each item on the exchange date.¹

A Section 355 spin-off shows how this plays out. You hold parent stock with a $300,000 basis. After the distribution you also hold subsidiary stock. On the distribution date the parent stock is worth $400,000 and the subsidiary stock $100,000, a combined $500,000. Your $300,000 basis splits 80/20: $240,000 to parent, $60,000 to subsidiary. Selling the subsidiary shares immediately at $100,000 produces $40,000 of gain, and the remaining deferred gain stays inside the parent stock’s reduced basis.

The whole allocation hinges on getting the FMV right. Publicly traded stock uses the trading price on the exchange date. Closely held stock usually needs a formal valuation looking at earning power, net worth, dividend-paying capacity, and comparable-company data. For private-company transactions, a professional valuation report is the documentation the IRS expects if the numbers are ever questioned.

Holding Period Carries Over

The holding period on your new stock doesn’t restart. Under Section 1223, you tack the holding period of the surrendered property onto the received property, as long as the new basis is determined by reference to the old basis (Section 358 provides that) and the old property was a capital asset or Section 1231 property at the time of the exchange.⁹

Held the original shares three years before a tax-free reorganization? The new stock qualifies for long-term capital gains treatment on day one. Section 355 distributions are treated as exchanges for holding period purposes, so spin-off shares also get the tack.

Boot property is the exception. Because boot takes a fresh FMV basis, its holding period starts on the exchange date. Sell boot within a year and any gain is short-term, no matter how long you held the original asset.

Recordkeeping and Penalty Exposure

Section 6662 imposes a 20% accuracy-related penalty on underpayments from substantial valuation misstatements, doubling to 40% for gross misstatements.¹⁰ Misallocating basis among received properties, or using the wrong starting basis, can clear that threshold quickly.

The regulations impose specific reporting duties for reorganizations. Each corporate party must attach a statement to its return identifying all parties, the transaction date, and the value and basis of transferred assets, broken out into categories including loss importation property, loss duplication property, property on which gain or loss was recognized, and everything else. Any significant holder in the exchange must file a parallel statement covering the basis and value of surrendered stock.¹¹

Keep your own records too: fair market value and adjusted basis for everything in the exchange, plus the supporting valuation for private stock or closing prices for public stock. Hold those records for as long as you own the received property and at least three years after the return reporting its sale. The basis you compute today often becomes the starting basis for the next Section 358 exchange, and a gap in the paper trail compounds through every subsequent transaction.

1
Office of the Law Revision Counsel. 26 USC 358 – Basis to Distributees
2
Office of the Law Revision Counsel. 26 USC 351 – Transfer to Corporation Controlled by Transferor
3
Office of the Law Revision Counsel. 26 USC 368 – Definitions Relating to Corporate Reorganizations
4
Office of the Law Revision Counsel. 26 USC 355 – Distribution of Stock and Securities of a Controlled Corporation
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Office of the Law Revision Counsel. 26 USC 362 – Basis to Corporations
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eCFR. 26 CFR 1.358-2 – Allocation of Basis Among Nonrecognition Property
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Office of the Law Revision Counsel. 26 USC 356 – Receipt of Additional Consideration
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Office of the Law Revision Counsel. 26 USC 357 – Assumption of Liability
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Office of the Law Revision Counsel. 26 USC 1223 – Holding Period of Property
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Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
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eCFR. 26 CFR 1.368-3 – Records to Be Kept and Information to Be Filed with Returns